The objective of this proposal is to further define the mechanisms of glucose across the placenta. We will quantitate the kinetics for glucose transport from mother to fetus across the intact guinea pig placenta and evaluate the role of inhibition of glucose transport in this preparation. Using microvillous membrane preparation from human and guinea pig placentas we will study the kinetics of glucose uptake in vitro. In addition, we will evaluate the role of sodium and of inhibitors in glucose uptake by the microvilli. We will attempt to identify the component(s) in the microvilli which are responsible for glucose transport and determine its (their) biochemical characteristics. These studies will broaden our understanding of placental glucose transport and may increase our understanding of the pathophysiology of diabetes in pregnancy and intrauterine growth retardation.